(1) Field of the Invention
This invention relates to a method for producing honeycomb-shaped metal moldings.
(2) Description of the Prior Art
Various uses of porous inorganic materials are being rapidly developed, employing them in diversified forms such as pellets, beads, rings and honeycombs depending upon the purpose of use. Among them, the porous inorganic materials in a honeycomb shape have come to play an important role as catalyst carriers or cores therefor due to a number of advantages inherent in the honeycomb shape, including (1) low pressure loss, (2) larger specific surface area, (3) easiness of handling and (4) smaller abrasive wear.
The conventional honeycomb-shaped moldings are mainly classified into:
(1) Extrusion-molded ceramics; and PA1 (2) Laminated structures consisting of flat and wavy or corrugated metal sheets. PA1 (A) Porous and good in adhesion of a coating agent or a catalyst; PA1 (B) Satisfactory in physical strength and hard to break; and PA1 (C) Chemically stable and non-influential on the catalyst activity.
These honeycomb structures are unsatisfactory as catalyst carriers. Namely, the catalyst carrier and the core material for the carrier are required to be:
The ceramic type carriers mentioned at (1) of the preceding paragraph exhibits the problem that the conditions of the heat treatment which satisfy the required physical strengths are inconsistent with the conditions of heat treatment which are necessary to achieve the desired porosity. The metallic carriers mentioned at (2) require complicated pretreatments to enhance the adhesion of the coating agent or the like. Accordingly, the provision of a suitable honeycomb-shaped metal molding remains an unfulfilled need.